This invention relates to recording apparatus and more particularly to a device for identifying patrols made by security personnel.

With existing arrangements security personnel are required to leave identifying cards each time they call at a prescribed address. This however has the disadvantage that multiple calls can be faked by personnel leaving several cards at the one visit. While it has been known to counter¬ act this through the use of key operated or other mechanically activated recording systems such apparatus are expensive and subject to vandalism.

It is an object of this invention to ameliorate the afore¬ mentioned disadvantages and accordingly a light sensitive time and date recording apparatus is disclosed, said apparatus being adapted for mounting behind a transparent barrier at a selected location to record times and dates of security patrols, said apparatus being activated by a portable torch of the type carried by said security patrol.

The currently prefered form of this invention will now be described with reference to the accompanying block diagram labelled 1 and schematic diagrams labelled 2, 2A, 2B and 2C.

SUBSTITUTE SHEET

In terms of the accompanying block diagram it may basically comprise a light sensitive diode or pulsed infrared sender unit 1 which is adapted to be mounted inside a window. The

signal from the detector 1 is fed into an event logger circuit 2 and thence to a memory circuit 3 where it is stored agaist a specific date and time as provided by clock 4. A liquid crystal display 5 is also incorporated into the recorder so that the user may subsequently observe the date and time for each of a series of prior recorded events ie. security patrols. Although not shown in the accompanying diagram provision may also be made for hard printouts of event times and dates. In order to prevent multiple logging of the same event an inhibiting switch 6 may also fitted. This prevents separate recordal of events less than say one minute apart.

Although the memory circuit 3 is not limited to any specific capacity it is envisaged that an abitity to record and store data for several patrol events per day over a two week period would be sufficient for most applications.

In use the light detector/sender unit 1 (or indeed the complete device if suitably compacted)

Preferred technical specifications are as follows

Case

Maximum Size: 140 x 90 x 40 mm Material: Moulded Black Plastic Thickness: 1.5 mm Back Cover: Black Plastic Thickness: 1.5 mm Securing: Phillips head self tapping countersunk

Front Panel

Aperture for green Event Record LED

Aperture for red Power On LED

Aperture for Event Count light sensitive diode

Fluorescent paint surrounding Event Detector aperture

Adhesive strip 45 x 15 mm, 3 mm from top and bottom

Back Cover

Aperture for a 4 digit x 5 mm, 7 segment display Keypad

Electronics

Memory: Record 256 events, with date and time Clock: Resetable ^" date and time

Twenty four hour time

One hundred year calendar

Accuracy +- 1 minute per month

Display: 4 digits with separator LEDs: Low current 3mm round

Red for power on

Green for event record

Light Sensor: Light sensitive diode

Not to trigger to ambient light

Triggered at night by a hand held torch

Keypad: 12 key, 0 - 9, *, #

Set date

Set time

Display current time and date

Display event time and date

Scroll through events

Battery: Life greater than one year for memory only

Six volt plug in dry cell

would be mounted safely inside a window so as to be secure from vandals.

On the event of each visit security personnel would need only to shine their torch through the window and onto the detector unit to automatically record and store the date and time of the patrol.

At the end of a selected period the client would then be able to confirm that the contracted number of patrols have in fact taken place by simply activating the readout through either the liquid crystal display or printout.

The electronics are mounted on two printed circuit boards, one for the display, mounting LCD1 and U3, and the other for the remaining electronics, mounting Ul, U2, U4 , U5 and their associated components .. The keypad mounts on the back panel .

With the preferred example all processing is carried outby a 68HC11 microprocessor Ul operating from an 8 MHz crystal XI. The 68HC11 is configured for single chip mode, having no external address and data lines. This microprocessor has onboard a 2K X 8 EEPROM which can be written to and read by the microprocessor and is non-volatile, allowing storage of events .

A real time clock is provided by U4 , operating from a 32.768 KHz crystal X2. Date and time setting and reading is carried out from the microprocessor via serial lines CLK, SIO and SRST. This RTC is battery backed with battery Bl to give a 10 year clock data retention. During normal operation this battery is trickle charged from the system power line via Dl and R6.

User control is provided by the keypad KP1 , the keys strokes of which are detected by the microprocessor via strobe lines KP1 and KP7. Commands are entered at the keypad to instruct the microprocessor to set time and date, display current time and date and to scroll through events. The keypad gives flexibility to provide other control functions at a later date.

A four digit data display is provided by the LCD display LCD1 and its controller chip U3. This chip continually scans each segment of each digit of the LCD, updating its display. Data to be displayed is entered into the controller chip by the microprocessor on lines Dl to D , whilst DSl to DS4 are used to set the digit to be updated with this data.

An event detector is provided by light detection diode D3 and its associated amplifier U5. The output of this amplifier is fed to the microprocessor onboard A-D converter via line PS. The microprocessor continually monitors this line, converting the analog signal to an 8 bit digital value. Over a period of time a background light level is established that provides a reference against which a guards torch is compared.

Event and Power indications are provided by LEDs LI and L2, driven from the microprocessor by lines EV and PO. In case of external power failure when the unit runs from battery these LEDs can be turned off to conserve power .

On power up the system hardware is set to a known state by the reset circuit provided by U2 and the reset switch SI. This unit also contains a watchdog which may be enabled by strapping LKl pins 2 and 3 or disabled by strapping LKl pins 1 and 2. When the watchdog is enabled

the processor will provide pulses on line WD to keep the watchdog from timing out and resetting the system,

It will thus be appreciated that this invention at least in the form of the embodiment disclosed provides a novel and unique improvement to existing methods for recording security patrols. Clearly however the example described is only the currently preferred form of this ^' invention and a wide variety of modifica ions may be made which would be apparent to a person skilled in the art. For example the invention extends to other electrically equivalent types of circuits and is not limited to any particular design of housing for the apparatus. Apparatus may also within the scope of this invention be adapted for use in applications outside the security industry .